Photographic silver halide emulsions containing 4-hydroxy quinolines



Patented Dec. 18, i951 PHOTOGRAPH-IO SILVER HALIDE EMUL- SIONS CONTAINING 4-HYDROXY QUIN- OLINES John David Kendall and Douglas James Fry, Ilford, England, assignors to Ilford Limited, Ilford, England, a British company No Drawing. Application May 5, 1949, Serial No. 91,639. In Great Britain May 8, 1948 This invention relates to photographic materials and particularly to photographic materials in which the light-sensitive layer consists of a silver chlorobromide emulsion.

It iswell known that the addition of various compounds to photographic silver halide emulsions has an effect on the colour of the developed image. Thus United States Patent No. 2,397,015 corresponding to British Patent No. 563,498 describes the production of photographic light-sensitive elements in which the light-sensitive layer is a silver chloride emulsion containing a quinoline compound of the formula:

\N Ra where R1 is an unsubstituted alkyl or aralkyl group, R2 is a hydrogen atom or an alkyl or aralkyl group (or R1 and R2 together constitute the residue of an alicyclic nucleus) and R3 is a hydrogen atom or a lower alkyl group. Derivatives of these compounds containing substituents (other than amino or substituted amino) in the carbocyclic ring and mineral acid salts of any of such compounds may alternatively be employed. By reason of the presence of these quinoline compounds the developed images obtained from the silver chloride emulsions have a. bluish tone.

The action of such compounds in modifying the tone of the developed image is highly specific and it is to be noted that United States Patent No. 2,397,015 corresponding to British Patent No. 563,498 claims the use of this narrow class of compounds for use with a certain specific type of emulsion.

It has now been found that in silver chlorobromide emulsions the tone of the developed image may be made warmer, i. e. inclining to a brownish-black, by including in such emulsions one or more of a narrow class of quinoline compounds, and according to the present invention silver chlorobromide emulsions which yield images of brown-black colour on development are obtained by including in the emulsion, during its manufacture, 4-hydroxy quinoline or a 4-hydroxy quinoline containing one or more nuclear substituents selected from alkyl, e. g. methyl, ethyl, propyl and butyl, acyl, e. g. acetyl, propionyl and butyryl, carboxy and carbalkoxy, e. g. carbethoxy groups. In the case of compounds containing carboxy groups the salts of such compounds, e. g. the sodium salts, may be employed.

7 Claims. (01. 957) Preferably, according to the invention, there is included in a gelatino silver chlorobromide emulsion, during the manufacture of the emulsion, a compound of the general formula:

R, on

wherein at least three of the groups R1 to Rs are hydrogen atoms and the remaining R groups are alkyl, acyl, carboxy or carbalkoxy, for example any of those listed above, but not more than one of the R groups is acyl, carboxy or carbalkoxy.

The proportion of the compound added to the emulsion will depend on the particular compound used. In general satisfactory brown-black tones are obtained using proportions of the order of 0.2 to 25 cc. of a 1% solution of the compound per pound of emulsion. The emulsion may be washed or unwashed.

It is an important advantage of the compounds of this invention and distinguishes them from other compounds which have some browning effect on the image colour, that the compounds are without any appreciable deleterious effect on the speed and contrast of the emulsion, and do not cause fogging of the emulsion.

tion

Examples A gelatino silver chlorobromide emulsion was: prepared and to portions of it were added pro-- portions of compounds according to this inven tion. Each compound was added at the rate of."

ggp Compound Image Colour 1 4-hydroxy quinoline Warmer than control.

4-hydroxy-8-methyl-quinoline Do. 4-hydroxy-6-methyl-quinoline Mucht ilvarmer than con r0 3-acetyl-4-hyclroxy-quinoline Do. 4-hdroxkyi-quino1ine-3-carbox- Warmer than control.

y lo ac 6 2-methyl-4hydroxy-quinoline. Do.

The following examples illustrate the inven--- The compound of Example was tested as the sodium salt.

Other compounds in the series gave very similar results.

What we claim is:

1. A photographic silver chlorobromide emulsion which yields images of brown-black tone on normal photographic development which emulsion includes 4-hydr0Xy-6-methyl quinolinethe proportion of the said compound being equivalent to 0.2 to 25 cubic centimeters of a 1% solution of the compound per pound ofemulsion.

2. A photographic silver chlorobromide emulsion which yields images of brown-black tone on normal photographic development which includes 3-acetyl-4-hydroxy quinoline the proportion of the said compound being equivalent to 0.2 to 25 cubic centimeters of a 1% solution ofthe compound per pound of emulsion.

3. A photographic silver chlorobromide emulsion which yields images of brown-black tone on normal photographic development which includes a compound selected from the class consisting of 4-hydroxy quinoline, 4-hydroxy quinolines containing a single nuclear alkyl substituent and 4-hydroxy quinolines containing in the 3- position acyl, carboxy and carbalkoxy groups, the proportion of the said compound being equivalent to 0.2 to 25 cc: of a 1% solution of the compound perpound of'emulsion.

4. A photographic element consisting of a paper support carrying a photographic silver chlorobromide' emulsion which yields images of brown-black tone on normal photographic development which includes a compound selected from the class consisting of 4-hydroxy quinoline, 4-hydroxy quinolines'containing a single nuclear alkyl'substitutent and 4-hydroxyquinolines containing in the 3-position acyl, carboxyl and carbalkoxy groups, the proportion of the said compound being equivalent to 0.2 to 25 cc. of a 1% solution of the compound per pound of emulsion.

. 5. A photographic silvenchlorobromide emulsion which yields images of brown-black tone on normal photographic development which emulsion includes 2-methyl-4-hydroxy quinoline, the proportion. of. the said compound being equivalent to 0.2 to 25 cc. of a 1% solution of the compoundzperi pound of emulsion.

6. A photographic silver chlorobromide emulsion: which yieldsimages of brown-black tone on. normal photographic development which emulsion includes 8'-methyl-4-hydroxy quinoline, the proportion of the said compound being equivalent to 0.2 to 25 cc. of a 1% solution of the compound per pound of emulsion.

7'. A photographic silver chlorobromide emulsion which yields images of brown-black, tone on normal. photographic development which emulsion includes. 4-hydroxy quinoline 3-carboxylic acid, the proportion of said compound being equivalent to 0.2 to 25 cc. of a 1% solution of the compound'per pound of emulsion.

JOHN DAVID KENDALL. DOUGLAS. JAMES FRY.

REFERENCES CITED The following referencesare of record in the file of'this patent:

UNITED STATES PATENTS Number Name Date 2,395,846 Carroll et al Mar. 5, 1946 2,397,015 Kendall et al Mar. 19, 1946 FOREIGN PATENTS Number Country Date.

No. 371 Great Britain 1896 596,105 Germany Apr. 26,1934 768,519 France Aug. 7, 1934 

3. A PHOTOGRAPHIC SILVER CHLOROBROMIDE EMULSION WHICH YIELDS IMAGES OF BROWN-BLACK TONE ON NORMAL PHOTOGRAPHIC DEVELOPMENT WHICH INCLUDES A COMPOUND SELECTED FROM THE CLASS CONSISTING OF 4-HYDROXY QUINOLINE, 4-HYDROXY QUINOLINES CONTAINING A SINGLE NUCLEAR ALKYL SUBSTITUENT AND 4-HYDROXY QUINOLINES CONTAINING IN THE 3POSITION ACYL, CARBOXY AND CARBALKOXY GROUPS, THE PROPORTION OF THE SAID COMPOUND BEING EQUIVALENT TO 0.2 TO 25 CC. OF A 1% SOLUTION OF THE COMPOUND PER POUND OF EMULSION. 